Scratch resistant coated glass article including carbide layer(s) resistant to fluoride-based etchant(s)

ABSTRACT

A scratch resistant coated article is provided which is also resistant to attacks by at least some fluoride-based etchant(s) for at least a period of time. In certain example embodiments, an anti-etch layer(s) is provided on a glass substrate in order to protect the glass substrate from attacks by fluoride-based etchant(s). In certain example embodiments, the anti-etch layer(s) is substantially transparent to visible light. In certain embodiments, a DLC layer(s) may be provided over the anti-etch layer. An underlayer may be provided under the anti-etch layer(s) in certain example embodiments. In certain example embodiments, the anti-etch layer(s) may be of or include a carbide and/or oxycarbide of Zr, Sn or the like.

This application is a divisional of application Ser. No. 10/989,721,filed Nov. 17, 2004 now U.S. Pat. No. 7,879,202, which claims priorityon Provisional Ser. Nos. 60/529,624, filed Dec. 16, 2003, and60/529,103, filed Dec. 15, 2003, and which is a continuation-in-part(CIP) of Ser. No. 10/899,305, filed Jul. 27, 2004 (now U.S. Pat. No.7,445,273), the entire disclosures of which are all hereby incorporatedherein by reference.

This application relates to a coated article including a coatingsupported by a glass substrate. The coating includes an anti-etch layerthat is resistant to fluoride-based etchant(s), and may also includeother layer(s) such as a scratch-resistant layer comprising diamond-likecarbon (DLC). Coated articles according to different embodiments of thisinvention may be used as windows or in any other suitable application.

BACKGROUND OF THE INVENTION

Unfortunately, vandals have increasingly been turning to glass etchantsas a tool of choice for graffiti. For example, graffiti on glass windowsof subway cars is commonplace. Vandals have been forming such graffition windows of subway cars, buildings, trains, buses and other glasswindows by using glass etchants which are capable of etching glass atlocations where such etchants are applied.

Armor-etch is an example of a bifluoride salt (e.g., ammonia bifluorideor sodium bifluoride) based paste used for etching patterns on glasssurfaces, and has been used in forming graffiti. The mechanism offluoride ion attack on SiO₂ of glass is summarized below for purposes ofexample only and understanding.

Though hydrogen fluoride (HF) does not dissociate well, active hydrogenfluoride paste reacts with silicate (which forms the matrix for glass)in the presence of water as in the following equations:HF₂ ⁻═HF+F⁻6HF+SiO₂═H₂SiF₆+2H₂O

An alternative type of glass etching material, which is also abi-fluoride based etchant, is sometimes referred to as B&B etching crèmemanufactured by B&B Etching Products. Ammonium bifluoride ((NH₄)HF₂) andsodium bifluoride (NaHF₂) salts are very soluble in water. For example,a 2.8 g/100 g solution of ammonium fluoride would produce a 1.7 g/100 gsolution of hydrofluoric acid (HF) at pH 1, with 85% of the fluorineatoms in the form of HF. At higher concentrations or higher pH, asignificant amount of the HF₂ ⁻ ion is present. Acidified fluorides canproduce substantial quantities of HF in solution.

The active ammonia bi-fluoride reacts with silicate in the presence ofwater as presented in the following equations:(NH₄)HF₂═(NH₄)⁺+HF₂ ⁻HF₂ ⁻═HF+F⁻6HF+SiO₂═H₂SiF₆+2H₂O

An equilibrium is established between the reactants and products. Thus,as hydrogen fluoride is consumed in reacting with the SiO₂ of the glass,more hydrogen fluoride is produced to maintain the equilibrium. The SiO₂etch rate (i.e., the etch rate of the glass) is linearly related to theHF⁻ and HF₂ ⁻ concentrations, and is not related to the F⁻ concentrationat any pH.

Conventional coatings used for fluoride resistance to protect glass fromsuch etchings are polymer-based film. Unfortunately, these coatings aresusceptible to damage and are not scratch resistant thereby renderingtheir use in environments such as subway cars, buses and vehiclesundesirable. Moreover, in some cases the film can be lifted and theetchant applied under the film.

Scratch resistant coated glass articles are known which utilize alayer(s) comprising diamond-like carbon (DLC) on the glass surface. Forexample, see U.S. Pat. Nos. 6,261,693, 6,303,226, 6,280,834, 6,284,377,6,447,891, 6,461,731, 6,395,333, 6,335,086, and 6,592,992, thedisclosures of which are all hereby incorporated herein by reference.While carbon is resistant to fluoride ion (and HF₂ ⁻) attack, theselayers when formed via ion beam deposition techniques at very smallthicknesses give rise to micro-particulates on the substrate. When suchlayers are very thin in nature, these micro-particles may give rise topinholes which are pathways for the HF to attack the underlying glass.Thus, scratch resistant coated articles which utilize only a layercomprising DLC on the glass are sometimes susceptible to the fluoridebased etchant attacks described above.

In view of the above, it can be seen that there exists a need in the artfor a scratch resistant coated article which is also resistant toattacks by fluoride-based etchant(s).

BRIEF SUMMARY OF EXAMPLES OF THE INVENTION

A scratch resistant coated article is provided which is also resistantto attacks by at least some fluoride-based etchant(s) for at least aperiod of time. In certain example embodiments, an anti-etch layer(s) isprovided on the glass substrate in order to protect the glass substratefrom attacks by fluoride-based etchant(s). In certain exampleembodiments, the anti-etch layer(s) is substantially transparent tovisible light.

In certain example embodiments, the anti-etch layer may be provided onthe glass substrate, along with an overlying scratch resistant layer ofor including diamond-like carbon (DLC).

In certain example embodiments, an underlayer(s) may be provided underthe anti-etch layer(s).

In certain example embodiments, the anti-etch layer(s) may comprise orconsist essentially of zirconium oxycarbide, hydrogenated zirconiumoxycarbide, tin oxycarbide, or hydrogenated tin oxycarbide. In certainexample embodiments, the optional underlayer(s) may comprise or consistessentially of silicon oxide, silicon nitride, and/or the like.

In certain example embodiments, there is provided a method of making acoated article, the method comprising providing a glass substrate, andsputtering a target comprising zirconium in an atmosphere comprisingoxygen and carbon so as to form a layer comprising zirconium oxycarbide.

In other example embodiments of this invention, there is provided amethod of making a coated article, the method comprising: providing asubstrate; and sputtering a target comprising zirconium and/or tin in anatmosphere comprising oxygen and carbon so as to form a layer comprisingzirconium oxycarbide and/or tin oxycarbide.

In other example embodiments of this invention, there is provided acoated article comprising a glass substrate; an anti-etch layercomprising zirconium oxycarbide and/or tin oxycarbide supported by theglass substrate, wherein the anti-etch layer is resistant to at leastsome fluoride-based glass etchants; and optionally a layer comprisingdiamond-like carbon (DLC) provided on the glass substrate over at leastthe anti-etch layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a coated article according to anexample embodiment of this invention.

FIG. 2 is a cross sectional view of a coated article according toanother example embodiment of this invention.

FIG. 3 is a cross sectional view of a coated article according toanother example embodiment of this invention.

FIG. 4 is a cross sectional view of a coated article according toanother example embodiment of this invention.

FIG. 5 is a cross sectional view of a coated article according toanother example embodiment of this invention.

FIG. 6 is a cross sectional view of a coated article according toanother example embodiment of this invention.

FIG. 7 is a schematic diagram illustrating an example method ofdepositing and/or forming an anti-etch layer according to an exampleembodiment of this invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Referring now more particularly to the accompanying drawings in whichlike reference numerals indicate like parts/layers throughout theseveral views.

Coated articles according to certain example embodiments of thisinvention may be used as subway car windows, transit bus windows, trainwindows, or other types of vehicle windows, or the like in differentapplications. Coated articles according to certain example embodimentsof this invention may also be used as architectural windows, inmonolithic or IG unit form. Coated articles such as windows according tocertain example embodiments of this invention may have a visibletransmission of at least about 15%, more preferably at least about 50%,more preferably of at least about 60%, and even more preferably of atleast about 70%. In certain example embodiments of this invention, anyof the coated articles discussed herein may or may not be heat treated(e.g., thermally tempered).

A scratch resistant coated article is provided which is also resistantto attacks by fluoride-based etchant(s). In certain example embodiments,an anti-etch layer(s) is provided on the glass substrate in order toprotect the glass substrate from attacks by fluoride-based etchant(s).In certain example embodiments, the anti-etch layer(s) is substantiallytransparent to visible light (i.e., the anti-etch layer if depositedalone would be transmissive to at least about 60% of visible light, morepreferably at least about 70% of visible light, and even more preferablyat least about 80% of visible light).

In certain example embodiments of this invention, single or multi-layercoatings according to example embodiments of this invention are able toresist HF attack on glass for twenty-four hours or so with no visiblesign of significant adverse effect. In example embodiments of thisinvention, such coatings have a dense structure, are characterized bylow pinhole density, and/or are characterized by substantial chemicalinertness (e.g., forming insoluble fluorides).

In certain example embodiments, the thickness of the anti-etch layer(see any layer 2 or 2′ herein) need not exceed about 0.9 μm (or 9,000Å). In certain example embodiments, the thickness of the anti-etch layer(2 or 2′) may be from about 50 to 9,000 Å, more preferably from100-5,000 Å. In certain preferred instances, the anti-etch layer (2 or2′) is preferably at least about 2,500 Å thick, and still morepreferably from about 3,000 to 5,000 Å thick. Although the anti-etchlayer may be thinner than this in certain example embodiments of thisinvention, if it is thinner than this then etch resistance may sufferundesirably. Moreover, when it is thicker than this range opticalproperties such as visible transmission or the like may suffer. We notehowever that t is possible for the anti-etch layer to be thicker (e.g.,from 9,000 to 20,000 Å) in certain instances.

FIG. 1 is a cross sectional view of a coated article according to anexample embodiment of this invention. The coated article includes aglass substrate 1 (e.g., soda lime silica glass, or borosilicate glasswhich may or may not be polished) which supports both an anti-etch layer2 and a scratch resistant layer 3 of or including DLC or the like.

The layer 3 of or including DLC may be any of the DLC inclusive layersdescribed in one or more of U.S. Pat. Nos. 6,261,693, 6,303,226,6,280,834, 6,284,377, 6,447,891, 6,461,731, 6,395,333, 6,335,086, and/or6,592,992, and may be deposited/formed in any of the manners describedin any of these patents, the disclosures of which are all incorporatedherein by reference. For example, and without limitation, DLC inclusivelayer 3 may be from about 5 to 1,000 angstroms (Å) thick in certainexample embodiments of this invention, more preferably from 10-300 Åthick. In certain example embodiments of this invention, layer 3including DLC may have an average hardness of at least about 10 GPa,more preferably at least about 20 GPa, and most preferably from about20-90 GPa. Such hardness renders layer (s) 3 resistant to scratching,certain solvents, and/or the like. Layer 3 may, in certain exampleembodiments, be of or include a special type of DLC known as highlytetrahedral amorphous carbon (t-aC), and may be hydrogenated (t-aC:H) incertain embodiments (e.g., from 5 to 39% hydrogen, more preferably from5 to 25% hydrogen, and most preferably from 5 to 20% hydrogen). Thistype of DLC includes more sp³ carbon-carbon (C—C) bonds than sp²carbon-carbon (C—C) bonds. In certain example embodiments, at leastabout 50% of the carbon-carbon bonds in the layer 3 may be sp³carbon-carbon (C—C) bonds, more preferably at least about 60% of thecarbon-carbon bonds in the layer 3 may be sp³ carbon-carbon (C—C) bonds,and most preferably at least about 70% of the carbon-carbon bonds in thelayer 3 may be sp³ carbon-carbon (C—C) bonds. In certain exampleembodiments of this invention, the DLC inclusive layer 3 may have adensity of at least about 2.4 gm/cm³, more preferably of at least about2.7 gm/cm³. Example linear ion beam sources that may be used to depositDLC inclusive layer 3 on substrate 1 via an ion beam include any ofthose in any of U.S. Pat. Nos. 6,359,388, 6,261,693, 6,002,208,6,335,086, 6,303,226, or 6,303,225 (all incorporated herein byreference). When using an ion beam source to deposit layer(s) 3,hydrocarbon feedstock gas(es) (e.g., C₂H₂), HMDSO, or any other suitablegas, may be used in the ion beam source in order to cause the source toemit an ion beam toward substrate 1 for forming DLC inclusive layer(s)3. It is noted that the hardness and/or density of layer(s) 3 may beadjusted by varying the ion energy of the depositing apparatus. The useof DLC inclusive layer 3 allows the coated article (e.g., monolithicwindow, or IG unit) to be more scratch resistant than if the coatingwere not provided.

In certain example embodiments of this invention, the glass substrate 1may be ion beam milled before the anti-etch layer 2 (or layer 4) isdeposited thereon. The ion beam milling of the glass substrate has beenfound to remove certain defects on the glass surface thereby resultingin a more durable end product. For example and without limitation, anyof the example techniques of ion beam milling described in U.S. Pat. No.6,368,664 may be used to ion beam mill the glass substrate 1 in thisregard, the disclosure of the '664 being incorporated herein byreference. In the FIG. 1 embodiment for example, after ion beam millingthe glass substrate (e.g., to remove at least about 2 Å of glass fromthe substrate, more preferably at least about 5 Å, and possibly at leastabout 10 Å), the anti-etch layer 2 may be deposited using magnetronsputtering or IBAD in different embodiments of this invention.Thereafter, the DLC inclusive layer 3 may be ion beam deposited over theanti-etch layer 2. Stack configurations may be produced by one-passin-line deposition in a suitably configured system, or in any othersuitable manner.

Anti-etch layer(s) 2 is provided to allow the coated article to beresistant to attacks by fluoride-based etchant(s) such as thosediscussed above. The anti-etch layer 2 may be deposited by sputtering,ion beam deposition, or ion beam assist deposition (IBAD) in differentembodiments of this invention. Anti-etch layer 2 substantially prevents(or reduces) fluoride-based etchant(s) such as those discussed abovefrom reaching the glass substrate 1 for at least a period of time (e.g.,for at least one hour, more preferably for at least twelve hours, andmost preferably for at least twenty-four hours), thereby rendering thecoated article more resistant to attacks by fluoride-based etchant(s)such as those discussed above. Moreover, since certain embodiments ofthis invention are used in the context of window applications, theanti-etch layer(s) 2 is substantially transparent to visible light.

It has been found that the inclusion of carbon into an inorganic layer 2or coating significantly improves the resistance of the coated glassarticle to corrosion by fluoride etching. In certain exampleembodiments, at least carbon inclusive reactive gas (e.g., acetylene(C₂H₂) and/or CO₂) is used during the deposition process of anti-etchlayer 2 in order to provide carbon in the resulting layer therebyimproving the corrosion resistance of the layer and the coated article.As shown in FIG. 1, the anti-etch layer 2 may comprise or consistessentially of zirconium oxycarbide (e.g., ZrOC), zirconium carbide(ZrC), hydrogenated zirconium oxycarbide (e.g., ZrOC:H), and/orhydrogenated zirconium carbide (e.g., ZrC:H). These materials areadvantageous in that zirconium carbide is very scratch resistant,thereby improving the mechanical durability of the coated article inaddition to being etch resistant. In this respect, zirconium carbide(even if it also includes oxygen) tends to be a very hard and durablematerial. In certain example embodiments of this invention, thezirconium carbide inclusive layer 2 may be formed (e.g., via sputteringor IBAD) so as to have an average hardness of at least about 20 GPa,more preferably of at least about 25 GPa, still more preferably of atleast about 27 GPa, and most preferably of at least about 29 GPa.

Moreover, another advantage associated with these materials is thatzirconium carbide (whether or not hydrogenated and/or oxided) is fairlyresistant to oxidation in environments where it is exposed to UV raysand/or water—this is an improvement over DLC alone in certain examplenon-limiting embodiments of this invention.

It has surprisingly been found that when Zr (or Sn as discussed below)is reactively sputter-deposited or otherwise deposited using a carboninclusive gas such as C₂H₂ plus O₂, or CO₂ (optionally in addition to Argas for example), the resulting coating and coated article realizessignificantly improved resistance to fluoride based etching compared toa situation where the Zr (or Sn) is reactively deposited using only O₂gas (in addition to Ar). It is believed that the surprisingly improvedresistance resulting from the inclusion of carbon in the gas and thusthe layer is due to the carbon's inert characteristics. While thesesurprisingly results are associated with Zr, the Zr may be replaced withany of the following materials in any layer 2 herein: Sn, Ti, Hf, V, Nbor Ta (it is expected that these surprisingly results will also beapplicable to these materials).

As mentioned above, the ZrC or ZrOC may be hydrogenated in certainexample embodiments of this invention. In hydrogenated embodiments(e.g., ZrC:H or ZrOC:H), the hydrogen content of the layer may be fromabout 1-40%, more preferably from about 5-35%, and even more preferablyfrom about 5-25%.

As explained above, when the DLC layer is provided, it is typicallydeposited by an ion beam technique over the Zr inclusive anti-etch layer2. In such instances, due to the high energy which may be used in ionbeam depositing DLC inclusive layer 3, the DLC may alloy with the Zr atthe interface between layers 2 and 3. Thus, a thin layer comprising analloy of Zr and DLC may be provided between layers 2 and 3 in certainexample embodiments of this invention.

FIG. 2 illustrates another example embodiment of this invention where anunderlayer 4 (e.g., silicon nitride, silicon oxide {e.g., SiO₂ or anyother suitable stoichiometry}, or silicon oxynitride) is providedbetween the glass substrate 1 and the anti-etch layer 2 discussed above.Of course, any of the aforesaid anti-etch layers 2 may be used as layer2 in this embodiment. In certain example instances, the underlayer 4(which is preferably a dielectric) has been found to further improve theetch resistance of the coated article by removing or reducing chemicalor other defects on the glass surface. In particular, it is believedthat the underlayer 4 of silicon oxide for example removes or reduceschemical defects on the surface on which the anti-etch layer is directlyprovided. Such defects may lead to growth defects in the anti-etch layer2 which can be weak points more susceptible to etchant attack. Thus, theremoval or reduction of such defects via the use of silicon oxide or thelike is advantageous in that etch resistance can be surprisinglyimproved. The silicon oxide or the like of the underlayer 4 may beformed in any suitable manner, such as by magnetron sputtering, flamepyrolysis (combustion-CVD), etc. An example advantage of combustion-CVDis that it is an atmospheric pressure process and does not requireexpensive hardware typically associated with low pressure processes suchas sputtering.

In certain example embodiments of this invention, any of the aforesaidunderlayers 4 may have a thickness of from about 30 to 800 Å, morepreferably from about 50 to 500 Å, and most preferably from about 100 to400 Å.

FIG. 3 illustrates another example embodiment of this invention wherethe anti-etch layer 2 alone is provided on the glass substrate. Thereneed not be any protective layer over the anti-etch layer 2 in thisembodiment. Again, any of the aforesaid anti-etch layers 2 may be usedas layer 2 in this FIG. 3 embodiment. In other words, the anti-etchlayer 2 in the FIG. 2-3 embodiments may be made of or include any of thematerials listed above with respect to layer 2 in the FIG. 1 embodiment.

It has been found that the deposition temperature for the anti-etchlayer 2 may in certain instances play a role in etch resistance. Incertain example instances, sputter-depositing anti-etch layer 2 atelevated temperatures results in unexpectedly improved etch resistance.In certain example embodiments, the anti-etch layer 2 (or 2′) isdeposited by sputtering onto a glass substrate 1 (with or without anunderlayer(s) 4 therebetween) at a temperature of at least about 100degrees C., more preferably of at least 200 degrees C., still morepreferably at least 300 degrees C., even more preferably of at least 400degrees C., and sometimes at least 450 degrees C. It is believed thatthe higher temperatures increase the energy provided during the layerformation process and increase the density of the layer therebyimproving anti-etch characteristics. However, in other exampleinstances, elevated temperatures are not used and the deposition maytake place at room temperature or the like.

As an alternative to using high temperatures when forming the anti-etchlayer, the anti-etch layer 2 may be formed using IBAD in certain exampleembodiments of this invention. Again, the advantage of using IBAD isthat the ion beam(s) used during IBAD layer formation adds energy to thelayer formation process and causes a more dense layer to be formed.Again, it is believed that this improves anti-etch characteristics ofthe layer 2. In an IBAD process, both an ion beam(s) and material from asputtering target(s) simultaneously impinge on the substrate in order toform the layer being deposited. FIG. 7 illustrates and example of usingIBAD to form/deposit anti-etch layer 2. As shown, in this IBADembodiment both an ion beam source(s) 26 and a sputtering deviceincluding a sputtering target(s) 50 are used. An ion beam B from the ionbeam source 26 intersects with the material M sputtered from thesputtering target(s) 50 proximate the surface where at least part of theanti-etch layer 2 (or 2′) is being grown, so that at least part of theanti-etch layer 2 is grown/formed by a simultaneous combination of boththe ion beam and sputtering. Substrate 1 is preferably moving indirection D during the layer formation process.

In a pure sputtering embodiment where anti-etch layer 2 (or 2′) isformed by sputtering only with no ion source, or alternatively in theFIG. 7 IBAD embodiment, gas including carbon such as gas comprising C₂H₂and/or CO₂ may be introduced to a sputtering chamber proximate thesputtering target 50 (e.g., of Zr, Sn or the like) so that a layer 2comprising ZrC:H and/or ZrC is formed on (directly or indirectly) thesubstrate 1. It will be appreciated that when it is desired tohydrogenate the layer, the gas should include hydrogen and may comprisea hydrocarbon gas for example (e.g., C₂H₂). In addition to the carboninclusive gas, gas(es) such as Ar and/or O₂ may also be introduced intothe sputtering chamber proximate target 50. When O₂ gas is alsointroduced in addition to C₂H₂ and/or CO₂ gas proximate the target 50,then a layer 2 comprising ZrOC:H and/or ZrOC is formed on (directly orindirectly) the substrate 1. An example gas introduction is 90 sccm ofAr gas and 20 sccm of C₂H₂ gas being introduced into the sputter zoneproximate the target 50. The sputter zone is typically at a pressureless than atmospheric pressure (e.g., at 2 to 3 mTorr). Moreover, whenion source 26 is used in the formation process for layer 2, then gassuch as Ar and/or C₂H₂ may be introduced into the ion source 26. In suchsituations, the ion source 26 may emit ions such as Ar ions, C ionsand/or H ions in beam B toward the layer formation area on thesubstrate.

As explained above, while Zr is used as a metal in the embodiments ofFIGS. 1-3, this invention is not so limited unless expressly claimed. Inthis respect, FIGS. 4-6 emphasize that the Zr in any of the embodimentsdescribed herein, or shown in FIGS. 1-3, may be replaced with Sn incertain example embodiments of this invention.

It is noted that any of the aforesaid materials for anti-etch layers 2(or 2′) may also be nitrided in certain example embodiments of thisinvention. In particular, nitrogen gas may also be used in thesputter-deposition process for example in order to at least partiallynitride the anti-etch layer in certain alternative embodiments of thisinvention. For example, and without limitation, the anti-etch layer 2may comprise or consist essentially of zirconium carbide oxynitride(e.g., ZrCON), zirconium carbide nitride (ZrCN), hydrogenated zirconiumcarbide oxynitride (e.g., ZrCON:H), and/or hydrogenated zirconiumcarbide nitride (e.g., ZrCN:H).

EXAMPLES

The following examples are provided for purposes of example only and arenot intended to be limiting unless expressly claimed.

Examples 1 and 2 formed a Zr inclusive layer using a Zr sputteringtarget on a glass substrate. The Example 1 layer was of ZrO and had nocarbon, whereas the Example 2 layer was of ZrOC:H and thus did includecarbon. By comparing Examples 1 and 2, it can be seen that the provisionof carbon in the layer significantly improve corrosion resistance of thelayer. The layers of Examples 1 and 2 were deposited on the glasssubstrate 1 using the following sputtering process parameters. Theparameters Ar, O₂, CO₂, C₂H₂, and N₂ illustrate how much gas flow wasused in the sputtering process in the sputtering chamber atmosphere foreach of these gases, in units of sccm. In each of Examples 1-2, a powerof 8 kW was used, 9 passes by the target were performed, the line ratewas about 15.4 inches per minute. The layer deposited in Example 1 endedup about 102 nm thick, whereas the layer in Example 2 ended up about 265nm thick.

Examples 1-2 Sputtering Process Parameters—Zr target

Ar O₂ CO₂ C₂H₂ N₂ Ex. 1 200 75 0 0 0 Ex. 2 200 0 50 50 0

Thus, it will be appreciated that given the gases used in sputtering theZr inclusive layers in Examples 1 and 2, the Example 1 layer was of ZrOand had no carbon, whereas the Example 2 layer was of ZrOC:H sincecarbon dioxide and acetylene gases were used and thus did includecarbon. The Example 1 coated article had a visible transmission of about75%, whereas the Example 2 coated article had a visible transmission ofabout 66%.

Examples 1-2 were then exposed to a fluoride etchant for the same amountof time in order to compare the corrosion resistance of the two layers.Surprisingly, it was observed that after about 3 minutes of exposure tothe etchant, about 100% of the Example 1 layer had been removed whereasabout 0% of the Example 2 layer had been removed. Moreover, after about10 minutes of exposure to the etchant, only about 5% of the Example 2layer had been removed due to the etchant, mostly via pinholes. Thus, itcan be seen by comparing Examples 1 and 2, that the provision of carbonin the layer significantly improve corrosion resistance of the layer. Inparticular, the Example 2 layer with carbon was much more resistant tocorrosion than was the Example 1 layer without carbon.

Examples 3 and 4 are additional examples of certain embodiments of thisinvention, where Zr inclusive anti-etch layers 2 were deposited on aglass substrate 1 via sputtering using Zr sputtering targets. In each ofExamples 3-4, a power of 8 kW was used, 9 passes by the target wereperformed, the line rate was about 15.4 inches per minute. The layerdeposited in Example 3 ended up about 285 nm thick, whereas the layer inExample 4 ended up about 172 nm thick.

Examples 3-4 Sputtering Process Parameters—Zr Target

Ar O₂ CO₂ C₂H₂ N₂ Ex. 3 200 10 0 50 50 Ex. 4 200 25 0 50 50

Thus, it will be appreciated that given the gases used in sputtering theZr inclusive layers in Examples 3 and 4, each of the anti-etch layers 2of Examples 3 and 4 was of hydrogenated zirconium carbide oxynitride(e.g., ZrCON:H). The Example 3 coated article had a visible transmissionof about 21%, whereas the Example 4 coated article had a visibletransmission of about 57%. Examples 3-4 were then exposed to a fluorideetchant for the same amount of time in order to compare the corrosionresistance of the two layers. Surprisingly, it was observed that afterabout 3 minutes of exposure to the etchant, about 0% of the Example 3layer and about 0% of the Example 4 layer had been removed. Moreover,after about 10 minutes of exposure to the etchant, only about 5% of theExample 4 layer and 0% of the Example 3 layer had been removed due tothe etchant.

Examples 5 and 6 formed a Sn inclusive layer using a Sn sputteringtarget on a glass substrate. The Example 5 layer was of SnO (probably aversion of SnO known as SnO₂) and had no carbon, whereas the Example 6layer was of SnOC and thus did include carbon and did not includehydrogen. By comparing Examples 5 and 6, it can be seen that theprovision of carbon in the layer significantly improve corrosionresistance of the layer. The layers of Examples 5 and 6 were depositedon the glass substrate 1 using the following sputtering processparameters. The parameters Ar, O₂, CO₂, C₂H₂, and N₂ illustrate how muchgas flow was used in the sputtering process in the sputtering chamberatmosphere where the target was located for each of these gases, inunits of sccm. In Example 5 a power of 20 kW was used and in Example 6 apower of 5 kW was used. In each of Examples 5-6, 1 pass by the targetwas performed, and the line rate was about 15.4 inches per minute. Thelayer deposited in Example 5 ended up about 79 nm thick, whereas thelayer in Example 6 ended up about 45 nm thick.

Examples 5-6 Sputtering Process Parameters—Sn Target

Ar O₂ CO₂ C₂H₂ N₂ Ex. 5 250 550 0 0 0 Ex. 6 250 0 460 0 0

Thus, it will be appreciated that given the gases used in sputtering theSn inclusive layers in Examples 5 and 6, the Example 5 layer was of SnOand had no carbon, whereas the Example 6 layer was of SnOC since carbondioxide was used and thus did include carbon. The Example 5 coatedarticle had a visible transmission of about 74%, whereas the Example 6coated article had a visible transmission of about 70%.

Examples 5-6 were then exposed to a fluoride etchant for the same amountof time in order to compare the corrosion resistance of the two layers.Surprisingly, it was observed that after about 3 minutes of exposure tothe etchant, about 15% of the Example 5 layer had been removed whereasonly about 10% of the Example 6 layer had been removed. Thus, it can beseen by comparing Examples 5 and 6, that the provision of carbon in thelayer improved corrosion resistance of the layer. In particular, theExample 6 layer with carbon was more resistant to corrosion than was theExample 5 layer without carbon.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

The invention claimed is:
 1. A coated article comprising: a glasssubstrate; an anti-etch layer comprising zirconium oxycarbide and/or tinoxycarbide supported by the glass substrate, wherein the anti-etch layeris resistant to at least some fluoride-based glass etchants; and a layercomprising diamond-like carbon (DLC) provided on the glass substrateover at least the anti-etch layer.
 2. The coated article of claim 1,wherein an interlayer comprising silicon oxide and/or silicon nitride isprovided between the anti-etch layer and the glass substrate.
 3. Thecoated article of claim 2, wherein the interlayer comprising siliconoxide and/or silicon nitride is from about 100 to 400 Å thick.
 4. Thecoated article of claim 1, wherein the anti-etch layer is locateddirectly on and contacting the glass substrate.
 5. The coated article ofclaim 1, wherein the coated article has a visible transmission of fromabout 10 to 90%.
 6. The coated article of claim 1, wherein the anti-etchlayer is at least about 2,500 Å thick.
 7. A coated article comprising: asubstrate; and an anti-etch layer comprising zirconium oxycarbide and/ortin oxycarbide supported by the substrate, wherein the anti-etch layeris resistant to at least some fluoride-based glass etchants.
 8. Thecoated article of claim 1, wherein the anti-etch layer compriseshydrogenated zirconium oxycarbide and/or hydrogenated tin oxycarbide. 9.The coated article of claim 8, wherein a hydrogen content of the layercomprising hydrogenated zirconium oxycarbide is from about 1-40%. 10.The coated article of claim 9, wherein a hydrogen content of the layercomprising hydrogenated zirconium oxycarbide is from about 5-35%. 11.The coated article of claim 10, wherein a hydrogen content of the layercomprising hydrogenated zirconium oxycarbide is from about 5-25%. 12.The coated article of claim 1, wherein the coated article is a window.13. The coated article of claim 1, wherein the coated article has avisible transmission of at least about 50%.
 14. The coated article ofclaim 1, wherein the layer comprising DLC has a hardness of at leastabout 10 GPa.
 15. The coated article of claim 14, wherein the layercomprising DLC has a hardness of at least about 20 GPa.
 16. The coatedarticle of claim 1, wherein the layer comprising DLC comprises highlytetrahedral amorphous carbon (t-aC).
 17. The coated article of claim 16,wherein the layer comprising highly tetrahedral amorphous carbon ishydrogenated.